1. Field of the Invention
Embodiments of the present invention relate to methods for distributing nanoparticles on substrate surfaces, more specifically to methods for forming and/or distributing nanoparticles in an ordered fashion on substrate surfaces.
2. Description of the Related Art
Experimental and theoretical aspects of highly ordered colloidal particle assemblies have received a great deal of attention in recent years. See, e.g., J. Rheol. 1990, 34(4) 553-590 by Ackerson, B.; Phys. Rev. Lett. 1981, 46(2), 123 by Ackerson, B; Phys. Rev. Lett. 2004 93(4), 04600-1 by Cohan, I., Mason, T. G., and Weitz, D. A.; Phys. Rev. E. 1998, 57(6) 6859-6864 by Haw, M. D. Poon, W. C. K., and Pusey, P. N.; Adv. Mater. 2004, 16(9), 516 by Pham, H. H., Gourevich, I., Oh, J. K., Jonkman, J. E. A., and Kumacheva, E.; G. M., Adv. Mater. 2005, 17, 1507-1511 by Winkleman, A., Gates, B., McCarty, L. S., and Whitesides; and Adv. Mater. 2005, 17(6), 657 by Shenhar, R., Norsten, T. B., and Rotello, V. M., all of which are incorporated herein by reference in their entirety.
In particular, arrangement of nanomaterials (or nanoparticles) in one dimension has been the focus of a considerable number of studies. Applications in, e.g., electronics, optics and medical science, etc., could benefit from the unique properties of these materials. See, e.g., Nano Letters. 2 (4) 289-293. (2002) by Xiangyang Shi, Shubo Han, Raymond J. Sanedrin, Cesar Galvez, David G. Ho, Billy Hernandez, Feimeng Zhou, and Matthias Selke, the entirety of which is incorporated herein by reference. If nanomaterials can be arranged into useful structures, a number of possible uses for nanoelectronic devices may arise. See, e.g., Journal of Physical Chemistry 102 (35) 6685-6687 (1998) by S.-W. Chung, G. Markovich, and J. R. Heath, the entirety of which is incorporated herein by reference.
A typical goal of arranging nanomaterials is the production of nano-scale conductive wires for electronics applications. While production of nanowires is commonly known in the art, production of substantially linear and ordered nanowires spanning several micrometers in length has posed a challenge.
Methods utilized in arranging nanoparticles into nanowires include vapor phase deposition, monolayer deposition, and dielectrophoresis. See, e.g., Langmuir 20, 11797-11801 (2004) by Robert Kretschmer and Wolfgang Fritzsche, and. Langmuir 20, 467-476 (2004) by Ketan H. Bhatt, Orlin D. Velev, all of which are incorporated herein by reference. Structures are typically difficult to achieve using these methods, and when formed are typically not single, straight lines but rather branched arrays of curved lines.
Literature on 1-D particle arrangements is limited, but an extensive review has been recently published. See, e.g., Adv. Meter., 2005, 17(8), 951 by Tang, Z. and Kotov, N. A., the entirety of which is incorporated herein by reference. The two most common types of nanowires are fibers and pearl-chain structures. Pearl-chain structures comprise a plurality of nanoparticles arranged in a pearl-like fashion. The most widely reported method for producing pearl-chain formations is dielectrophoresis, and other electrochemical or electrostatic processes. See, e.g., Langmuir, 2004, 20 11797-11801 by Kretschmer, R., Fritzsche, W.; G. M., Adv. Mater. 2005, 17, 1507-1511 by Winkleman, A., Gates, B., McCarty, L. S., and Whitesides; and Langmuir, 2004, 20, 467 by Bhatt, K. H., and Velev, O. D., all of which are incorporated herein by reference.
Pearl-chain structures produced by methods commonly available in the art tend to be curved and can be at least a few nanoparticles wide. The earlier work has primarily focused on 2-D and 3-D ordered arrangements of nanoparticles. Nanoparticle arrays reported in the literature typically contain tens of lines, precluding their use in applications such as, e.g., state of the art electronics devices, for which substantially straight and thin conductive nanowires are desired.